The invention relates to a method for supporting a structure, in which method there is arranged below the structure a cohesion structure, which transfers the structure load through shaft adhesion to surrounding ground and the structure to be supported is arranged to be supported to said cohesion structure.
The invention further relates to an arrangement for supporting a structure, which arrangement includes a cohesion structure, which transfers the structure load through shaft adhesion to surrounding ground and which cohesion structure is arranged below the structure, whereby the structure is arranged to be supported to said cohesion structure.
Structures are typically supported with support piles and friction piles. The lower tip of a support pile is supported, for instance, on a rock or a dense bottomset bed. Thus, the support pile transfers major part of its load through the tip onto the rock or the dense bottomset bed. Friction piles are typically used when the rock or the dense bottomset bed is covered by a thick earth layer of moraine or other coarse-structured material. The friction pile transfers major part of the load through shaft friction to an earth layer surrounding it. In case the use of the support or friction pile is not possible, for instance, due to the fact that the distance between the ground surface and the rock, the dense bottomset bed or an earth layer suitable for the friction pile is large, it is possible to use a cohesion pile for supporting the structure. The cohesion pile transfers the pile load through adhesion created on its skin surface. Typically, the ground where a cohesion pile is used is compressive. Consequently, it is challenging to render sufficient the adhesion of the cohesion pile and the ground surrounding it. An example of a cohesion pile is disclosed in publication WO 91/04376.
The pile may be made, for instance, of wood, steel or concrete. A wooden pile is subjected to decay because of moisture in the soil and variation therein. On the other hand, concrete and steel piles are subjected to corrosion and the erosive effect, for instance, of chemicals in the soil.